1. Field of the Invention
The present invention relates to a manual charging apparatus for a vacuum interrupter, more particularly, to a manual charging apparatus for a vacuum interrupter including a safety device to protect a worker when working for charging a spring of an open/close device using a manual charging handle.
2. Description of the Conventional Art
In general, a vacuum interrupter is a device used in an extra-high voltage/high voltage distribution lines, which protects life and load appliances by cutting off a circuit by a vacuum suppression method in a vacuum interrupter within a circuit breaker by a separate signal of an external electric relay when an abnormal current such as an over current, a ground fault, a short current, and the like is generated. Such a vacuum interrupter is disposed within a circuit breaker together with other electric appliances for operation or control of power plants or substations, or operation of motors.
The vacuum interrupter uses a spring for closing or trip operations. In this instance, a motor is used to charge the spring, and the spring is charged by use of the motor. The motor is driven electrically, while manually rotated when an electric power is not available.
FIG. 1 is a perspective view illustrating a front side of a vacuum interrupter according to a conventional art, and FIG. 2 is a perspective view illustrating a rear side of a vacuum interrupter according to a conventional art, in which FIG. 1 shows that a front panel of the vacuum interrupter is removed and FIG. 2 shows that a rear panel is removed.
When a motor 1 is driven, the rotational force of the motor 1 is transmitted to a charging shaft 3 via a chain 2 so that the charging shaft 3 is rotated. When the charging shaft 3 is rotated, a charging pawl 4 connected to the charging shaft 3 pushes a tooth of a charging gear 6 fixed to a main shaft 5 one by one, thereby rotating the charging gear 6.
When the charging gear 6 is rotated, a charging cam 7 fixed to the main shaft 5 is rotated in the clockwise direction based on the drawing. As the charging cam 7 is rotated, a charging lever 9 tenses a closing spring 10 while rotating at the center of the lever shaft 9a, and the charging pawl 4 prevents a counter-rotation of the charging gear 6.
When the main shaft 5 is rotated at a predetermined angle, the closing spring 10 is in a maximally elongated state to accumulate energy in a closing standby state, and in this instance an operation piece 11 of a limit switch is turned to operate the limit switch so that the motor 1 is turned off.
When a closing latch 12 is released by a closing signal of the vacuum interrupter, a closing roller pushes the charging lever 9 by an instantaneous elastic energy of the closing spring 10 to rotate the charging lever 9 at the center of a lever shaft 9a, as a result, a link mechanism (not shown) connected to the charging lever 9 is interworked therewith, thereby moving a closing lever up to a closing position so that a closing operation is completed. Concurrently, a trip spring 14 is charged and an opening standby state.
FIG. 3 shows a manual charging handle according to a conventional art.
In general, the motor 1 is operated by a control power to tense the closing spring 10, but in some instances the motor 1 may be manually rotated and in this case, a manual charging handle H is used for such purpose.
When the manual charging handle H is rotated after being inserted into the charging shaft 3, the closing spring 10 is charged. In this instance, a power is transmitted in a state that a protrusion formed on the manual handle H is inserted into a groove formed on the charging shaft 3.
However, in such a vacuum interrupter according to a conventional art has a disadvantage in that when a power is turned on suddenly or erroneously during a manual charging work, the charging shaft 3 is rotated at a high speed by the motor 1 and the rotational force is transmitted to a worker, thereby causing injury to the worker.
Such a conventional art may be referred to as Korean Patent No. 10-0319405 and Korean Patent No. 10-0479672.